The present invention relates generally to barcode scanners, and, more specifically, to windows thereof.
One type of barcode scanner is configured for being mounted flush to a counter in a retail establishment such as a grocery supermarket. The scanner includes a housing containing a laser and cooperating optical elements for projecting a pattern of scan lines outwardly therefrom for engaging a barcode on a merchandise item.
A window is disposed atop the scanner housing for transmitting the laser scan lines from the housing to the item, with light reflected from the barcode being returned through the window for decoding in the scanner. The window includes a typically flat frame with an aperture therethrough in which a transparent pane of glass is suitably mounted for transmitting both the scan lines and their reflected light.
In typical operation, the grocery items are dragged individually over the window in sliding contact therealong instead of being lifted thereover. Accordingly, the window pane is typically mounted below the top surface of the frame to prevent snagging of the grocery items which would slow the scanning process and possibly damage the window pane. However, recessing the pane can provide a step or lip around the aperture which can also snag grocery items, as well as provide a pocket in which debris may accumulate over time.
To eliminate these problems, the window pane may be mounted flush in its frame in various manners having different advantages and disadvantages including complexity and cost. For example, the window pane may be removably mounted by resting atop an upwardly facing pocket formed in the frame around the aperture. The pane must be suitably resiliently supported to prevent damage thereto which correspondingly decreases the ability for maintaining a substantially flush or smooth top surface with the frame to prevent snagging.
A difference in elevation between the top of the pane and the top of frame of as little as about a few mils can cause objectionable snagging and potential damage to the pane. It is difficult in practice to achieve a flush mount in view of the large tolerances in thickness typical in the manufacture of the glass pane, and in the depth of the pocket.
Improved accuracy of mounting the pane in its frame may be obtained by mounting the pane from below the frame in a corresponding downwardly facing pocket. This however increases the complexity of the pane itself since a top extension thereof is required to extend through the aperture to an elevation flush with the top surface of the frame. The pane extension may be provided by machining a step around the perimeter of the pane for providing an upwardly extending plateau disposed flush with the frame top surface. Or, a thin glass laminate may be bonded to the top of the pane for otherwise producing the required step.
In this way, the bottom of the stepped pane may be precisely fixedly mounted inside the frame with the top of the step being disposed flush with the top of the frame. Although the resulting flush mounted pane provides acceptable performance, the mounting thereof is relatively complex and expensive.
Accordingly, it is desired to provide an improved barcode scanner window having a flush mounted window pane therein in a simple and inexpensive construction.
A barcode scanner window includes a frame having an aperture, and window pane disposed therein. The pane is smaller than the aperture and is bonded therein by an adhesive.